The objective of the proposed research is to establish in vitro conditions for the assembly of functional E. coli S30 ribosomes from precursor S16 RNA and the protein components. Precursor S16 RNA will be isolated and used to reconstitute a "precursor particle" which is an efficient substrate for methylation and cleavage of precursor RNA. The matured precursor particle will then be converted to S30 ribosomal subunits by addition of the remaining complement of S30 ribosomal proteins. The individual reactions and components will be fractionated and their importance in the assembly and function of the S30 ribosome determined.